New Hill, NC (WRAL) -- A quarter-inch crack in the reactor at the Shearon Harris nuclear plant in southwest Wake County, North Carolina has forced Duke Energy to take the plant offline.

No radioactive material leaked from the plant, and the public is not in danger according to Duke Energy officials.

Duke spokeswoman Kim Crawford said she couldn't say how long the reactor would be out of commission, but she said the utility has plenty of capacity and wouldn't need to purchase electricity from outside sources to meet demand.

Shearon Harris provides power to about 500,000 customers.

"Initial evaluation indicates that the flaw is not through wall, and there is no evidence of leakage based on inspections performed on the top of the reactor vessel head during the spring 2012 refueling outage," the NRC event report states.

The last unplanned shutdown at Shearon Harris occurred in August 2008 because of a leaking condenser. It also was taken offline in August 2003 because of a water pump failure.